Sanding and polishing machine



Dec. 17, 1968 F. F. SHERMAN ETAL 3,415,261

SANDING AND POLISHING MACHINE 4 Sheets-Sheet 1 Filed Oct. 19, 1966 INVENTORS AT am QR Nsw AE w FL m H F Tm mai owm L m r %w m 1968 F. F. SHERMAN ETAL 3,436,251

SANDING AND POLISHING MACHINE 4 Sheets-Sheet 2 Filed Oct. 19, 1966 FLOYD F. ROBERT E. ST'PLE-S BY masow imunAk ATTORNEYJ wwrw F. F. SHERMAN ETAL, 3,4163% SANDING AND POLISHING MACHINE Dec. 17, 1968 4 Sheets-Sheet :5

Filed Oct. 19, 1966 mmv NM Om mo ATTORNEYS United States Patent This invention relates to sheet material finishing machines, and more particularly to automatic machines for sanding and polishing sheet, or strip, material.

A general object of the present invention is to provide a sanding and polishing machine in which the material to be finished will be automatically conveyed to a sanding head for finishing, and, after sanding, will be inverted and automatically carried to a second sanding head for finishing the other side.

A more specific object of the invention is to provide a machine of this nature wherein the sanding head has a unique motion which is the resultant of two independent forces working at right angles to one another.

Another object of the invention is to provide a sanding head which is of such construction as to allow uniform sanding even where surface irregularities are present.

A further object is the provision of sanding apparatus wherein the sanding head is vertically adjustable relative to the material path so as to adapt the device to material of different thickness.

Still another object of the invention is the provision of a sanding head which will have guided horizontal movement at a predetermined distance above the path of material moving through the device, which head will have a resilient pad as a back-up member for the abrasive material used in the sanding operation.

Other objects of the invention will become apparent from the following description of one practical embodiment thereof, when taken in conjunction with the drawings which accompany, and form part of, this specification.

In the drawings:

FIGURE 1 is a side elevation of a sanding and polishing machine embodying the principles of the present invention;

FIGURE 2 is an enlarged fragmentray top plan view of the machine in the region of one of the sanding heads;

FIGURE 3 is a side elevation of that portion of the machine shown in FIGURE 2;

FIGURE 4 is a longitudinal vertical section taken on the line 4-4 of FIGURE 2;

FIGURE 5 is a vertical transverse section taken on the line 5-5 of FIGURE 3; and

FIGURE 6 is a vertical transverse section taken on the line 66 of FIGURE 3.

In general, the sanding and polishing machine of the present invention includes a conveying means for receiving sheet material from a source of supply, transporting it through one or more sanding and polishing stations, and delivering the finished material from the machine. If both sides of the material are to be finished, means will be included for inverting the sheet of material intermediate the two sanding stations. The motion of the sanding heads at each of the sanding stations will be the resultant of forces which tend to move the heads longitudinally of the conveyor means and transversely of the conveyor means.

Referring to the drawings in detail, and first particularly to FIGURES 1 and 5, the machine includes a lower table 1 and an upper table 2, which is spaced above, and parallel to, the lower table. The lower table is supported upon suitable legs 3, and the upper table 3,416,261 Patented Dec. 17, 1968 is supported by legs 4 which rest upon the lower table 1. Table 1 has a flat top 5, which extends from end to end of the machine, and channeled sides 6. Bracing members 7 may be employed at appropriate places along the table length to provide adequate rigidity. The upper table 2 will be of similar construction and need not be described in detail.

At the ends of table 1, there are bearings 8 which support shafts 9. These shafts carry rollers 10 which serve to mount, and drive, a conveyor belt 11. The rollers are so located that the upper flight of the belt rests upon the top 5 of the lower table 1. One of the shafts 9, in the form illustrated the one at the right of FIGURE 1, will be a driven shaft and carry a pulley 12. Pulley 12 is driven by a belt 13 from a motor 14 mounted on a platform 15 below the table 1.

Table 2 also has bearings 16 at its ends, the bearing supporting shafts 17 which carry rollers 18. A conveyor belt 19 is trained about the rollers 18. Here, again, the top flight of the belt slides upon the table top. One of the shafts 17 has a drive pulley 20, which carries a belt 21 driven from a motor 22, mounted upon a platform 23 which is supported above table 2 upon posts 24.

At the right end of table 2, as viewed in FIGURE 1, there is an inclined chute 25 which will deliver sheets of material to be finished to the upper flight of belt 19. It will be noted from the direction arrows in FIGURE 1 that the sheets of material will be moved across the top of the upper table through a sanding and polishing station 26. This will sand the upper surface of the sheet, as will be described, and the sheet will then move to the end of the table 2 and drop off onto the projecting end of table 1. The upper flight of belt 11 on table 1 is moving in the opposite direction to the conveying action of belt 19, and as the lower end of the sheet of material strikes belt 11, that end will be carried forward so that the sheet of material will tilt about the belt 19 as it passes around the roller 18, causing the sheet to be inverted and fall upon the top flight of belt 11 with its unsanded side uppermost. The sheet will then be carried along on belt 11 through a second sanding and polishing station 27, and then delivered from the end of the machine.

As the mechanism at the two sanding and polishing stations 26 and 27, and the driving means on the two platforms 15 and 23 are identical, only station 26 will be described in detail. The mechanical parts at station 27 have been given the same reference numerals as those used in the description of station 26.

Referring now particularly to FIGURES 2 through 6 of the drawings, it will be seen that the sanding station 26 includes two interconnected sanding heads 28 and 29. Here, again, the two heads are identical and only one will be described. The same reference numerals are applied to similar parts of both heads.

Each sanding head includes a plate 30 which extends transversely of the table above, and parallel to, the conveyor belt, and has its ends slidably mounted in guide grooves 131 of mounting slides 32 fixed to the sides of the table. Mounting slides 32 have depending mounting plates 33, which contain vertical slots 34 to receive securing bolts 35 which project through the vertical webs of the channeled sides of the table. When bolts 35 are tightened, the mounting plates 33 are held tightly against the table sides in positions of vertical adjustment. When bolts 35 are loosened, the mounting slides 32 can be adjusted vertically by means of adjusting screws 36, which are threaded through ears 37 projecting from the table side. The slides 32, and consequently their guide grooves 31, can be moved vertically by manipulation of the adjusting screws 36 to determine the height of the plate 30 primed.

ahead adjusted position, they canbe secured in place by tightening bolts 35.

On the upper side of plate 30, near each end, there is a bearing 38. These bearings support the ends of a shaft 39 which extends centrally lengthwise of the plate. There is a bracket 40 mounted at each side of each bearing 38, and opposed pairs of brackets 40 support abrasive sheet rollers 41. An abrasive sheet 42, such as sand paper, will be rolled upon one of the rollers 41 and have its opposite end carried beneath plate 30 and secured to the other roller 41. By reason of this arrangement, the sheet can be advanced from one roller to the other to present fresh abrasive surfaces to the sanding area as required. A resilient pad 43 is secured to the underside of plate 30, and sheet 42 passes beneath this pad, in order to provide a yielding backing for the arbrasive sheet. Each roller 41 carries a ratchet 44 adjacent one end, and there is a pawl 45 for cooperation with the ratchet to hold the rollers 41 against undesired movement. Pawl 45 is pivotally mounted upon astud 46 carried by a plate 47 secured to the upper side of bracket 40. Each roller 41 has a hand grip 48 at one end to facilitate rotation of the roller and advancing of the abrasive sheet. The sheet can be advanced by lifting the pawl from the ratchet on the roller from which the paper is to be drawn and rotating the other roller. The pawls will be returned to their normal position of engagement with the ratches by means of springs 49.

It will be noted from FIGURE 5 that plate 30 is shorter than the total distance from the bottom of one guide groove 31 to the bottom of the opposite guide groove, but is long enough so that if it is seated in one groove its opposite end will be within the groove in the opposite mounting slide. By reason of this arrangement, the plate can move transversely of the table and also longitudinally of the table, yet be held at all times by the guide grooves to movement within the plane for which the mounting slides are adjusted.

The movement of the plate is accomplished by cams on two cam shafts, a cam shaft 50 to impart a force component in a direction longitudinally of the table, and a cam shaft 51 for imparting a force transversely of the table. The movement given the sanding head will be the resultant of these two forces.

Cam shaft 50 is mounted in bearings 52 which are .seated upon brackets 53 fixed to the table. The cam shaft carries two pairs of cams, one pair 54 being used to impart longitudinal movement to the sanding head 28, and the other pair 55 being used to move sanding head 29. The cams are of the eccentric type, and carry straps '56. The straps are connected to the ends of links 57, and the opposite ends of the links are connected to arms 58 projecting from the shaft 39. It will be obvious that rotation of the cam shaft will impart an oscillatory movement to the links and the shaft 39, which force will be carried to the plate 30. The use of the pivotally connected links 57 will permit the plate to move transversely of the table during the longitudinal travel imparted by the cams 54. Shaft 50 carries a pulley 59 which is driven by belt 60 from a suitable motor 61.

Cam shaft 51 is mounted in bearings 62 supported upon brackets 63 at one side of the table. The shaft carries a pulley 64 at one end, about which a belt 65 is trained. The belt is driven by a suitable motor 66.

Shaft 51 carries two cams 67, one to control sanding head 28 and the other to control sanding head 29. Each cam has an encircling strap 68 connected to one end of a link 69. The other end of the link is pivotally attached to a connector member 70, which is mounted for vertical swinging movement upon a pivot pin 71 held by straps 72 mounted on the bearings 39 that support shaft 39. This provides a connection from the cam shaft to the sanding head whereby transverse movement may be imabove the conveyor belt: When theslidesare i-n-proper 4 par-ted to'the heads-yet leave-the-head-freeto-respond to the longitudinal force imparted from cam shaft 50.

The movement of the plate during a sanding operation will he the result of the two forces imparted by the two cam shafts. This movement can be a straight line, angular, oscillatory movement, or it may be an orbital one, depending upon the phase setting of the cams on the respective cam shafts. As the two sanding heads 28 and 29 are connected to the same cam shafts, the movements of the two heads will be similar.

At the entrance and exit sides of the respective sanding heads, there are hold-down rollers 73, 74, 75 and 76. Rollers 73 and 76 are mounted in slots 77 of support barckets 78 carried by the table. Springs 79 are connected to the roller shafts and to the table to yieldingly hold the rollers 73 and 76 against the conveyor belt -so as to hold successive work pieces in contact with the belt, and against movement relative to the belt, during the sanding operation. Rollers 74 and 75 are mounted in slots 80 in brackets '53, which support the bearings for cam shaft 50. These 'last mentioned rollers are urged downwardly by springs 81.

When the machine is to be used, motors 14 and '22 will be started to begin movement of the conveyor belts 11 and 19. Motors 61 and 66 will also be started so that the several sanding heads at the sanding and polishing stations 26 and 27 will be in operation. Work pieces, such as wooden sheets, panels, etc., will slide down chute 25 onto the top flight of conveyor belt 19, to be carried to the left, as viewed in FIGURE 1, to the sanding and polishing station 26. As the work piece reaches station 26, it will pass under hold-down roller 73 and then travel beneath sanding head 28, then under hold-down rollers 74 and'75, beneath sanding head 29 and'hold-down roller 76, and then continue of the end of table 2. At this time, the front end of the work piece will tilt downwardly and fall upon belt 11 on the lower table. The movement of the belt will cause the lower end of the work piece to move forward and the piece to be inverted as previously described. The Work piece will then be carried to the sanding and polishing station 27 where the operation previously described for sanding what is now the bottom of the work piece will occur upon the upper surface. After the second sanding operation the work piece will be discharged from the machine.

" There are times when it may be desirable to sand, or polish, only one side of the work piece. This can be done in either of two ways. The work pieces canenter by chute 25 and pass through sanding and polishing station 26, then be removed from the machine at the end of table 2, or the work pieces can be introduced directly onto the conveyor belt 11 of the lower table and pass through sanding and polishing station 27 only.

When that portion of the abrasive sheet 42 which is directly beneath the plate 30 becomes Worn, the operator may lift the appropriate pawl 45 from its ratchet 44 and rotate the other roller 41 to bring a fresh area of the abrasive sheet into place beneath the plate. As soon as the pawl is released it will move back into engagement with the ratchet, and the sheet is then locked against movement in either direction.

If work pieces of different thicknesses are to be put through the machine, bolts 35 which hold the mounting slides 32 will be loosened and the slides will be raised or lowered as required by manipulation of adjusting screws 36. When the mounting slides are in proper positions, bolts 35 will be tightened to hold them against movement. Vertical adjustment of the mounting slides will change the spacing of plates 30 from the conveying belt, so as to accommodate the sanding heads to the work piece thickness.

It will be clear from the above, that the motion of the sanding heads is at an angle to the direction of movement of the Work pieces through the machine. This results in a very high quality finish on the work pieces. The

particular movement of the sanding heads can be varied, if desired, by changing the relative phase of the cams of the cam shafts 50 and 51. The use of a resilient pad 43 between the plate 30 and abrasive sheet 42 provides a yielding backing for the abrasive sheet, so that the sheet may adjust itself to irregularities which may be present in the surface of the work piece.

While in the above one practical embodiment of the invention has been disclosed, it is to be understood that the particular details of structure which have been shown and described ,are merely by way of illustration, and the invention may take other forms within the scope of the appended claims.

What is claimed is:

1. A sanding and polishing machine comprising, a table, means to convey work pieces along the table, means defining guide grooves parallel to and above the conveyor means at either side of the table, a plate having its ends in the guide grooves and slidable in the grooves in the direction of movement of the conveyor means and transversely thereto, rollers carried by the plate at either side of the plate, an abrasive sheet wound upon the rollers and underlying the plate intermediate the rollers, means to impart a reciprocating force to the plate in a direction parallel to the direction of movement of the conveyor means, and means to simultaneously impart a reciprocating force to the plate transversely to the direction of movement of the conveyor means.

2. A sanding and polishing machine as claimed in claim 1, wherein there are means to adjust the guide groove defining means vertically to vary the distance of the plate above the conveyor means.

3. A sanding and polishing machine as claimed in claim 2 wherein, there are releasable means to hold the rollers against rotation.

4. A sanding and polishing machine as claimed in claim 1 wherein, there is a resilient pad secured to the underside of the plate to provide a resilient backing for the abrasive sheet.

5. A sanding and polishing machine as claimed in claim 1 wherein, the means to impart a reciprocating force to the plate in a direction parallel to the direction of conveyor means movement includes a camshaft transversely to the table at one side of the plate, cam-following means, and a link pivotally connected to the camfollowing means and the plate, and the means to impart a reciprocating movement to the plate transversely to the conveyor means movement includes a camshaft parallel to the direction of conveyor means movement, cam-following means, and a link pivotally connected to the parallel camshaft and the plate.

fit

6. A sanding and polishing machine as claimed in claim 5 wherein, there are second guide groove defining means, a second plate, rollers and abrasive sheet on the opposite side of the transverse camshaft, second camfollowing means on the transverse camshaft, and a link pivotally connecting the second cam-following means and the second plate, and there is a second cam-following means on the parallel camshaft and a link pivotally connecting the parallel camshaft second cam-following means and the second plate.

7. A sanding and polishing machine as claimed in claim 6 wherein, there are independent means to adjust vertically the first-mentioned guide groove defining means and the second guide groove defining means to vary the distance of the respective plates above the conveyor means.

8. A sanding and polishing machine as claimed in claim 7 wherein, there are releasable means to hold the rollers against rotation.

9. A sanding and polishing machine as claimed in claim 8 wherein, there are resilient pads secured to the undersides of the plate and second plate to provide resilient backing for the abrasive sheets.

10. A sanding and polishing machine as claimed in claim 9 wherein, there are hold-down rollers above the conveyor means at either side of the plate and second plate, and means to yieldingly urge the hold-down rollers toward the conveyor means.

11. A sanding and polishing machine as claimed in claim 1 wherein, there are second guide groove defining means spaced from the first mentioned guide groove defining means, a second plate carrying rollers and an abrasive sheet slidable in the second guide groove defining means, means to impart reciprocating movement to the second plate in a direction parallel to the direction of movement of the conveyor means and transversely thereto, and means to invert work pieces intermediate the plate an dsecond plate.

References Cited UNITED STATES PATENTS 2,165,616 7/1939 Cox 5159 897,951 9/1908 Yarnell -Q 51-59 3,094,815 6/ 1963 Pendergast 5 l 2,284,556 5/1942 Brackett 5l--59 JAMES L. JONES, 111., Primary Examiner.

U.S. Cl. X.R. 51-76, 359

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,416,261 December 17, 196E Floyd F. Sherman et al It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

printed specification, lines 4 and 5, "United In the heading to the New York, N. Y. should read U. S. Plywood- States Plywood Corporation, Champion" Papers Inc.

Signed and sealed this 10th day of March 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

1. A SANDING AND POLISHING MACHINE COMPRISING, A TABLE, MEANS TO CONVEY WORK PIECES ALONG THE TABLE, MEANS DEFINING GUIDE GROOVES PARALLEL TO AND ABOVE THE CONVEYOR MEANS AT EITHER SIDE OF THE TABLE, A PLATE HAVING ITS ENDS IN THE GUIDE GROOVES AND SLIDABLE IN THE GROOVES IN THE DIRECTION OF MOVEMENT OF THE CONVEYOR MEANS AND TRANSVERSELY THERETO, ROOLERS CARRIED BY THE PLATE AND EITHER SIDE OF THE PLATE, AN ABRASIVE SHEET WOUND UPON THE ROLLERS AND UNDERLYING THE PLATE INTERMEDIATE THE ROLLERS, MEANS TO IMPART A RECIPROCATING FORCE TO THE PLATE IN A DIRECTION PARALLEL TO THE DIRECTION OF MOVEMENT OF THE CONVEYOR MEANS, AND MEANS TO SIMULTANEOUSLY IMPART A RECIPROCATING FORCE TO THE PLATE TRANSVERSELY TO THE DIRECTION OF MOVEMENT OF THE CONVEYOR MEANS. 